Publisher's Synopsis
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1916 edition. Excerpt: ... however, open to the following objections: (1) It carries a relatively small amount of water and contains a very small steam space for its nominal horsepower. (2) It foams or primes very easily. (3) It is hard to keep the upper ends of the flues tight when the boiler is working heavily because they are not surrounded by water. (4) It requires Fig. 2.--Submerged Tube Vertical Boiler. careful attention on the part of the engineer to prevent the pressure from passing from the safe to the danger point because they hold only a small amount of water. This type is being superseded by the other two although there are a few still being built. Return Flue Boilers.--This type approaches in principle the Scotch marine boiler. It has a cylindrical shell resembling a large drum in shape, which is set horizontally. In the lower half of the boiler there is a cylindrical flue containing the furnace which terminates in a back chamber at the rear. Around the sides and over this furnace are a large number of fire tubes extending from the back connec Fio. 4.--Water Front Return Tube Boiler. tion to the uptake to the smokestack at the front (Fig. 3). The flue may have either a corrugated or flat surface. The corrugation increases enormously the resistance to deformation by pressure, but it has the drawback that it is difficult to keep it clean. Some makes of boilers of this type have water around the back connection as well as between the lower part of the flue and the shell (Fig. 4). Back connections which are not protected by means of water have cast-iron plates to prevent burning out of the shell. The hot gases pass back through the flue to the back connection and forward again through the tubes to the smokestack at the front. The advantages of these...
